Doors on vehicles are known. Such doors typically have a transparent window portion and a door frame surrounding and supporting the window. The door frame must be strong enough to support the window and to absorb and to dissipate forces on the door. Those forces may be from closing or slamming the door or may be vibrational stresses experienced during operation of the machine or vehicle.
U.S. Pat. No. 8,042,859 (“Kimoto”) issued Oct. 25, 2011 is an example of prior art related to doors. FIG. 3 of Kimoto discloses a car door of a vehicle. The car door includes glass windows, and a door frame including an outer panel (not shown) and an inner panel. The larger of the two glass windows may be lowered. The door frame is configured to receive the window when it is lowered. In the disclosure of Kimoto, the window area is a relatively small part of the entire door area. Thus, structural stresses applied to the car door of Kimoto have a relatively large door frame area over which the stresses may be absorbed and/or dissipated. Disadvantageously, the door of Kimoto is not beneficial for use on machines and industrial vehicles because the relatively small window size inhibits the visibility desired by machine and industrial vehicle operators. A better design is needed that provides the desired visibility and the strength to withstand structural loads on the door without adding substantial weight to the vehicle.